Um...a few quick questions, When your username changes, and someone dedicated a work to you, the name just changes right? The dedication is still dedicated to me despite the new username?
And the works and challenges and such under the current username, they just change to your new username right?

Okay, I've checked into it and here's the deal. Chances are you can still log in with your new username. However, you will no longer be able to access your older archived posts and most options to update or change things will no longer work.

I'm going to update this FAQ so the question about myOtaku will include this information.